Is mercury contamination in Everglades making birds gay?

Scientists have long suspected high mercury levels in the Everglades might be crimping the breeding efforts of wading birds.

A new study of white ibises by University of Florida researchers suggests the pollutant could have a far more profound impact than imagined: It turned a good chunk of a captive flock gay.

The study, published online Wednesday in a biological journal, documented a number of changes in the mating behaviors and reproductive success of four groups of ibises fed varying levels of mercury over a three-year period.

By far the most surprising effect was on the courtship inclinations of male ibises. In the first year, 55 percent of the males given the highest doses of mercury in their feed hooked up with other males during breeding season.

"They pretty much did everything except lay eggs," said Peter Frederick, a UF wildlife ecologist who led the study. "They built nests, they copulated, they sat in the nests together."

While the study raises concerns about mercury impacts on wildlife, Frederick flatly dismissed the idea of extrapolating the result to humans, saying that would be a serious misreading.